Gear testing apparatus



Dec. 16, 1952 w. A. SCHULTE GEAR TESTING APPARATUS 4 Sheets-Sheet 1Filed Aug. 12, 1946 FIG.

INVENTOR.

WILLIAM A. SOHULTE ATTORNEYS Dec. 16, 1952 w. A; SCHULTE GEAR TESTINGAPPARATUS 4 Sheets-Shet 2 Filed Aug. 12, 1946 INVENTOR.

WILLIAM A.SCH.ULTE

ATTORNEYS Dec. 16, 1952' w. A. SCHULTE 2,621,417}

GEAR TESTING APPARATUS Filed Aug. 12, 1946 4 Sheds-Sheet 3 FIG.4.

. WILLIAM A.SCHULTE 1 ,Aew 1 1i ATTORNEYS FIG.5.

Dec. 16, 1952 w. A. SCHULTE GEAR TESTING APPARATUS 4 Sheets-Sheet 4Filed Aug. 12, 1946 FIG].

FIG 9.

INVENTOR.

WILLIAM ASCHU LTE W ATTORNEYS Patented Dec. 16, 19 52 GEAR TESTINGAPPARATUS William A. Schulte, Allen Park, Mich, assignor to NationalBroach & Machine Company, Detroit, Mich., a ccrporationof MichiganApplication Augus'tlZ, 1946,'S erial No. 689,928

9 Claims. 1

The present invention relates to gear testing measuring apparatus andmore particularly-tea combination lead checker for checking the accuracyof lead of. spur or helical gears, and for measuring the pitch radiusthereof. Thisis'a continuation-in part of United States applica tionSerial No. 549,701 filed August 16, 1944, now' Patent No. 2,511,418.

Briefly described, the present apparatus com prises a work support formounting a'gear for rotation about its axis, and a checker supportmovable generally radially toward and "away'fr'om saidwork'support.Carried by. the checker support is a transversely adjustable head havingmeans associated therewith for effecting fine adjustment oftheheadrela-tive to the checker. support in a direction parallel to theaxis of the gear. Rota'tably mountedon the head is a sine barhavingapair of nose pieces or feelers adjust ably mounted-thereon forsimultaneous adjustment in and out with respect to the axis of rotationof the sine bar. Means are associated with the sine bar for indicatingwith a high degree of accuracy any motion in rotation which is impartedto thesinebar by moving the nose pieces or feelers into a tooth spaceortoothspaceson a gear whose lead is being checked.

It will be-appreciated thatin the event a spur gear is being checkedforaccuracy of lead,.the nose pieces or feelers will be engaged in a singletooth space. If, however, the lead check- 1s being made on a helicalgearit is firstnecessary to compute or refer to tables to determinethe'exact spacing necessary between the nose pieces or pieces are engaged ina tooth space or tooth spacesof a gear, and when the nose pieces have aform such that they contact the sides of the tooth space or spaces atpitch line thereof, the position of the checker support with referenceto the zero position indicates precisely the pitch diameterof the gear.

With the foregoing general description in mind, it is an object of thepresent invention to provide a simple and easily operated apparatusadapted; to effect quick andaccur'a'te checking 'of "helical to providealea'd'. checker of the'type described in which means are provided foradjusting'the gear contacting instrumentalities axially of the' gear byfineincrements sons to *providef'orabcurate seating thereof in a toothspace or tooth" 7 spaces without the ne'cessit'y'of 'eiiecting rotationof the gear; It is a furtherobject'of the present invention to providegear checking'apparatus" characterized by the high degree of accuracyobtainable, the simplicity of the constructionthereof, the' ease andsimplicity of operation thereof; and its adaptability to'perform a" dualfunction of checking lead and checking pitch diameter with a singlesetting of the'gear.

Other objects and features of the invention will become apparent as the"description proceeds,

'- especially whent'aken in conjunctionwith the accompanying drawings;wherein:

Figure 1 is a sideelevati'onof the improved gearchecking appa'ratuswiththe parts broken away;

port; 7

Figure 3 is a planelevatio'n of the checker" sup ort? Figure 4 isa'section on the line 4+5 Of'Fi'gureS; Figure 5 is' a section on theline 5-5 of Figure 25' Figure 6 is a perspective View of the head car-'rying the gear contacting elementsof the checking apparatus;

Figure '7 is a fragmentary'elevation'of means for setting the pitchradius gauge to zero Figure Sis a fragmentary section on line 8;

Figure 3; and

Figure 9 is'a diagrammatic view ofthe ball hearings on the fixture head.I

Referringfirst to Figure 1, there is indicated a main frame It -havinghead and tailstocks' II and I2, respectively, for supporting a gearabout to be checked. The present machine is'pa'rticu-' larly useful inchecking lead and pitch diameter of relatively large gears, although itwill'be ape preciated that the principles are equally appli cable tochecking small gears. However, the 'ap-" paratus illustrated is designedfor checking'rela tively large gears and hence constitutes arela' tivelymassive piece'of equipment: Mounted'on the base it and movable alongways (not shown) which extend parallel to the axis of the gear G is amain shoe adapted to be moved axially of the gear by a suitable reedscrew mechanism indicated generally at 2|. The main slide 20 is providedadjacent its top with ways indicated at 22 and shoable therein is achecker support which is movable horizontally in a directionperpendicular to the axis of the gear so as to move gear contactingmechanism substantially in a true radial direction with respect to theaxis of the gear G. A hand wheel 31 is provided for effecting movementof the support 30 toward and away from the gear. Main slide 20 in useconstitutes a part or the stationary base.

Mounted on the forward end of the checker support 30 and as bestillustrated in Figure 6 is a relatively adjustable head 45 which ismounted on the checker support 30 for movement transversely thereof andin a direction parallel to the axis or the gear G. A crank 41 isprovided which operates a pinion 42 (Figure 4) which meshes with a rack43 for effecting fine adjustment of the head 45 axially of the gear G.

As best seen in Figures 4 and 5, the checker support 30 is movable alongthe ways 22 by rotation of the hand wheel 3! which rotates bevel gears32 and gears 33 which imparts rotation to a lead screw 34 havingthreaded engagement with a feed nut 35 projecting upwardly from the mainslide 25.

The head 48 is provided with a disc 44 which is mounted for rotationtherewith about a pivot pin 45. Secured to the front face of the disc 44is a sine bar 46 which is rotatable therewith about the axis of thepivot pin 45. The pin 45 is provided with a ball bearing 41 in the headwhich retains the pin and hence the disc 44 against both axial andradial displacement. In addition, the disc 44 is provided with hardenedan-.

nular rings 48 which cooperate with a similar hardened ring 49 carriedat the front face of the head 40.

As best seen in Figures 5, 6 and 9, an annular ball bearing race I40 isinterposed between between hardened rings 48 and 49. Race MD, asindicated diagrammatically in Figure 9, is arranged to provide hardenedballs MI in groups of three, the groups being spaced at 120 intervalsaround the race. This insures three point bearing at all times, andtends to prevent injury to the hardened plates which might otherwiseresult if balls were continuous around the race. Greater insurance ofstability can be obtained over the conventional thrust type antifrictionbearing, in such an application, by closely grouping the balls (orrollers) in three equally spaced arcuate areas. This arrangement alsoserves to better distribute the load between respective balls and theiradjacent surfaces thereby reducing the maximum imposed stress therein.This valuable feature, as will be readily understood, has a wideapplication and its utility is not limited to a checking instrument ofthe type shown herein.

In order to limit relative rotation of the disc 44 and the sine bar 46 apin 50 is provided which projects forwardly from the head 40 through thehardened plate 49 and extends into a short arcuate slot (not shown)concentric with the pin 45 which is formed in the hardened plate 48.

Referring now to Figure 6, the sine bar 45 is provided with a pair ofslots or ways 5! having ways 52 in the bottom thereof in which isslidably mounted a key (not shown). Blocks 53 carrying the nose piecesor feelers 54 are slidable along the sine bar 45 and have bolts 55extending into the slots 5! and having threaded engagement with the keysreferred to. Thus by loosening the bolts 55 the blocks 53 may be slidalong the sine bar 46 to any desired position of adjustment.

In the operation of the device, sensing of errors in lead isaccomplished by indicating deviation of the sine bar 46 from a truehorizontal position or a position parallel to the axis of the gear Gbeing checked. In order to initially set the sine bar 46 in its trueparallel or zero position an anvil 55 is provided on the head 48. Thesine bar 45 is provided with an ear 51 having a rear wardly projectingpin 58 which is adapted to actuate the arm 59 of an indicator gauge 50.A removable gauge block Si is provided which is adapted to rest on theanvil 56 and the pin 58 will rest against the upper surface of gaugeblock 6! when the sine bar 46 is in zero position. At this time thegauge may be set by conventional mechanism to indicate zero. The gaugeblock BI is conveniently carried by a chain 62 so that it cannot becomeseparated from the measuring device.

The forwardly projecting portion 45a of the pin 45 which is located onthe axis of rotation of the gauge blocks 61 serves as a gauging surfacefrom which the blocks 53 are set. It will be appreciated that the methodemployed in measuring variations in true lead is to set the gauge blocksequal distances from the gauging surfaces of the pin projection 450:,these distances being computed or determined from reference to tablessuch that when the nose pieces or feelers 54 are firmly seated inadjacent tooth spaces of a helical gear, no rotation will be imparted tothe sine bar 46 if a true lead is present on the gear teeth. If,however, an error in lead is present in the gear teeth it will beappreciated that the sine bar 45 will be slightly rotated from its zeroposition and that the indicator gauge 60 will give an indication of theamount of rotation of the sine bar 46 and hence an indication of theamount and direction of lead error.

In the event that the gear whose lead is being checked is a spur gear,it will of course be appreciated that the problem is simplified in thesense that the feelers 54 may be located any convenient but equaldistance from the portion 45a of the pin 45 and that if a true lead ispresent in the spur gears, the sine bar will remain in its zero positionwhen the feelers 54 are firmly seated. However, with spur gears,transverse adjustment of the head 40 will not result in alignment offeelers 54 with tooth spaces, and thus with heavy gears care must beexercised to avoid injury to the feelers 54 in rotating the gear toalign tooth spaces with the nose pieces or feelers.

However, in the event that the gear being checked is a relatively heavygear, the final movement of the nose pieces 54 into the tooth space ortooth spaces of the gear will be accompanied by a suitable slightadjustment of the head 40 in a direction parallel to the axis of thegear by manipulation of the hand wheel 4!. This will properly align thenose pieces 54 with their respective tooth spaces and will avoid placinga strain on the delicate measuring instrumentalities. It will beappreciated of course that if the gear being checked is a relativelylight gear, an equivalent result could be obtained by efiecting a slightrotation of the gear. However, where the gear is heavy it is as apractical matter impossible to effect slight rotations thereof without 5imposing severe side strains on the feelers 54 which would affect. theaccuracy of the device.

Where the checking apparatus is to be employed in determining the pitchdiameter of the gear G, additional gauge and actuating devices areemployed.

Referring now to Figures 2, 3, '7 and 8, there is shown an abutment iscarried by the checker support it. Mounted on the top of slide 28adjacent ways 22 is an indicator gauge ll having an actuating finger E2.The abutment it is positioned on the checker support 39 in such aposition that its spacing from the end of the actuating finger '12 formsa measurement of the pitch radius of a gear when a feeler or feelerssuch as 54 are seated in a tooth space or tooth spaces of a gear G. tobe checked so as to engage the tooth surfaces at the pitch line thereof.For this purpose the nose pieces 5-i are preferably conical and theircone angle corresponds to the pressure angle of the gear being checked.Conveniently the spacing between the abutment l5 and the finger T2 ofthe gauge ii is effected by providing a series of gauge bars 53 slidablein a V-way on top of slide 2d. If desired, the gauge bars '53 mayinclude an element whose length can be varied by very small incrementsso as to provide in effect a micrometer adjustment for the spacingmeans.

Referring now particularly to Figure 8, there is indicated mechanisminsuring accuracy in reading the pitch radius measured. Secured to slide20 adjacent gauge H is a housing ifil having a spring biased plunger if!therein. Spring H2 is relatively strong, and as gauge blocks it (Figure2) are moved to the left by abutment spring 172 insures that they firmlyinterengage before plunger ill moves to impart movement to gauge fingeri2.

Housing llil has a pair of ears E15 on its top, the surfaces Hi3 betweenthe ears being accuratelymachined. Carried by checker support 3:) is ablock I'll which has pivoted thereto a gauge piece H8. Finger piece H9is secured thereto for swinging gauge piece lit to the position shown inFigure '7. To operate, checker support 39 is moved to the right as seenin Figure 2 until gauge piece I i8 registers with the slot betweenmachined surfaces lit. at which time gauge piece lit is swung into theslot to check accuracy of position of checker support 33. equivalent tothe known pitch radius corresponding to the. position of checker support39 are in place, and gauge ii is set to zero.

One of the advantageous features of the present invention is that ineffecting both lead and pitch diameter, an initial set-up is providedsuch that a zero indication of the respective gauges will indicate bothtrue lead and predetermined pitch diameter. Furthermore, variations inpitch diameter and lead will appear directly as plus and minus readingson the respective indicator gauges. It will be appreciated that inchecking lead of a relatively wide gear it is preferable to set thefeelers 54 the maximum distance apart so as to increase accuracy ofreading. In other words, with a wide gear of small helix angle there maybe two or three possible settings of the feelers 54 in which at theclosest setting the feelers would engage adjacent tooth space while inthe position of furthest separation they might engage tooth spacesseparated by one or more others.

While there has been illustrated and described in considerable detail apreferred embodiment of apparatus for checking lead and pitch diameterAt this time cause bars of gears, it will be appreciated thatequivalentdevices could. be produced for checking either lead or pitchdiameter alone and that the complete illustration and. description ofthe preferred embodiment of the present invention has been given merelyto enable those skilled in the art to practice the invention, the scopeof which is indicated by the appended claims.

What I claim as my invention is:

1. Lead checking apparatus comprising a Work ing to seat in differenttooth spaces of a helical gear while remaining in the plane defined bythe intersecting axes aforesaid.

2. Lead checking apparatus comprising a work support for mounting agear, a checker support relatively movable toward and away from saidwork support, a head on said checker support adjustable thereon in adirection parallel to the axis of a gear on said work support, a pair ofspaced feelers on said head mounted for movement about a second axisintermediate said feelers and perpendicular to and intersecting'the gearaxis, means for adjusting said feelers toward and away from said secondaxis, and measuring means for indicating movement of said feelers aboutsaid axis when said. feelers are in firm contact on both sides with oneor more tooth spaces of a gear on said work support.

3. Lead checking apparatus comprising a work support for mounting agear, a checker support relatively movable toward and away from saidwork support, a head on said checker support adjustable thereon in adirection parallel to the axis of a gear on said work support, a pair ofspaced feelers on said head mounted for movement about a second axisintermediate said feelers and perpendicular to and intersecting the gearaxis, means for adjusting said feelers toward and away from said secondaxis; and measuring means for indicating movement of said feelers aboutsaid axis when said feelers are in firm contact on both sides with oneor more tooth spaces of a gear on said work support, and adjusting meansfor making fine adjustments of saidhead relative to a gear.

l. Lead checking apparatus comprising a support for a gear to bechecked, a checker support movable radially of said gear, a sine barrotatable on said checker support about an axis radial of said gearhaving a zero position parallel to the axis of said gear, a pair offeelers adapted to seat in tooth' spaces of said gear, said feelersbeing spaced apart equal distances on opposite sides of the axis ofrotation of said sine bar, said distances being such that for a gearhaving true lead, said feelers will seat in adjacent tooth spaces of ahelical gear without rotating said sine bar, and a gauge for indicatingslight rotation of said sine bar to indicate error in lead, said feelerbeing adjustable radially of said sine bar to accommodate gears ofvarious leads.

5. Gear checking apparatus comprising a frame, a work support for a gearto be checked on said frame, a checker support movable on said 7 frametoward and away from said work support, a sine bar on said checkersupport extending generally parallel to the axis of a gear on said worksupport, a rotary support for said sine bar having" an axisperpendicular to and intersecting the axis of ,the gear, and feelers onsaid sine bar at opposite sides of the axis thereof independentlyadjustable longitudinally thereon toward and away from its axis, andindicator mechanism for measuring deviation of said sine bar fromparallelism with the axis of the gear.

6. Apparatus as defined in claim 5 in which said sine bar has anindicator actuating member, said checker support is provided with ananvil having a gauge surface adjacent the memher, and a removable gaugeblock to be interposed between said anvil and said member to set saidindicator at zero.

7. Lead checking apparatus comprising a base,

a work support on said base for mounting a gear to be checked, a checkersupport movable on said base toward and away from said work support, ahead on said checker support adjustable thereon in a direction parallelto the axis of the gear to be checked, a sine bar rotatably mounted onsaid head for rotation about an axis perpendicular to and intersectingthe axis of the gear to be checked, a pair of spaced feelers on saidsine bar at opposite sides of the axis of rotation thereof, means foradjusting said feelers independently longitudinally of said sine bar topositions such that for a gear of correct lead said sine bar is parallelto the axisof the gear, an indicator on said head positioned to indicatemovement of said sine bar out of parallelism with the axis of the gearto be checked, cooperating abutments located respectively on said baseand said checker support, means intermediate said abutments forsupporting gauge blocks, rigid mounting means for one of said abutmentspermitting sliding movement of said abutment relative thereto in adirection toward and away from said other abutment, spring meansopposing movement of said movable abutment in a direction away from saidother abutment, an indicator adjacent said mounting means in positiontobe actuated by movement of said movable abutment relative to itsmounting means.

8. Lead checking apparatus comprising a base, a work support on saidbase for mounting a gear to be checked, a checker support movable onsaid base toward and away from said work support, a head on said checkersupport adjustable thereon in a direction parallel to the axis of thegear to be checked, a sine bar rotatably mounted on said head forrotation about an axis perpendicular to and intersecting the axis of thegear to be checked, a pair of spaced feelers on said sine bar atopposite sides of the axis of rotation thereof, means for adjusting saidfeelers independently longitudinally of said sine bar to positions suchthat for a gear of correct lead said sine bar is parallel to the axis ofthe gear, an indicator on 8, said head positioned to indicate movementof said sine bar out of parallelism with the axis of the gear to bechecked, cooperating abutments located respectively on said base andsaid checker support, means intermediate said abutments for supportinggauge blocks, rigid mounting means for one of said abutments permittingsliding movement of said abutment relative thereto in a direction towardand away from said other abutment, spring means opposing movement ofsaid movable abutment in a direction away from said other abutment, anindicator adjacent said mounting means in position to be actuated bymovement of said movable abutment relative to its mounting means, andlocating means comprising cooperating members carried by said base andchecker support engageable when said checker support is in positioncorresponding to zero pitch diameter of a work gear, said abutmentsbeing directly engageable at such time to permit accurate zero settingof said last mentioned indicator.

9. Gear checking apparatus comprising a base.

a work support on said base for supporting a gear to be checked, a sinebar movable on said support toward and away from the gear, meansmounting said sine bar for rotation about an axis perpendicular to andintersecting the axis of the gear, means on said sine bar spaced equallythereon from the axis thereof disposed to enter into one or more toothspaces of the gear to be checked when the sine bar is parallel to theaxis of the gear, if the helix angle or lead of the gear teeth iscorrect, means for indicating movement of said sine bar out ofparallelism with the gear axis to indicate an error in lead, additionalmeans for indicating the displacement of said sine bar radially from theaxis of said gear so as to give a simultaneously measurement of thepitch diameter of the gear.

WILLIAM A. SCHULTE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date Re. 22,953 Praeg Dec. 23, 19471,303,198 Harris May 6, 1919 1,538,564 Leon May 19, 1925 1,862,146 HokeJune 7, 1932 2,026,784 Hansen Jan. 7, 1936 2,295,296 Fraumann Sept. 8,1942 2,336,747 Palmquist Dec. 17, 1943 2,345,298 Semar Mar. 28, 19442,476,189 Guetzkow July 12, 1949 2,504,961 Braaten Apr. 25, 1950 FOREIGNPATENTS Number Country Date 460,008 Great Britain Jan. 19, 1937

